Time Travel 1191
Almost Anonymous writes "Ronald Mallett, a physicist at the University of Connecticut, believes he knows how to build a time machine - an actual device that could send something or someone from the future to the past, or vice versa. He plans to have a working mockup this fall. For all those doubters, he assures people that "I'm not a nut"." Uh-huh.
Umm... (Score:4, Interesting)
Poignant. (Score:5, Interesting)
I have no idea how physicists approach the question of the creation of a contrafactual timeline which removes its own motive for existing (if his father lived, then he wouldn't create the time machine, and thus etc. etc.) But I think this is more interesting, if tragic, as a story of a man who still misses his father than as a viable line of research.
Irony (Score:2, Interesting)
So say he builds his time machine, goes back in time, and saves his father. Now he did that in a "parallel universe" (according to the article), and so now in this universe he doesn't invent time travel because his father is alive.
In conclusion: this man will not invent time travel, because if he does, it must only happen in a parallel universe.
Hmm... (Score:2, Interesting)
We should be encouraging these people (Score:5, Interesting)
Seems to me that's a great reason to become a physicist. Imagine what kind of creativity we could produce if the reply to something like that was "Cool! Here's some books to help you," rather than "You're crazy. That can't happen, so go do something else."
Re:He's either a fruit that's a little nutty... (Score:2, Interesting)
That is not true at all. We haven't met any time travelers because you can not send anything back to before the machine is built. To go back 10 years you need to run a time machine for at least 10 years. All that is happening is that it opens a wormhole to itself, you can not just open one to any time in the past. (This might sound like sci-fi BS, but this comes from actual scientists)
ways around the time travel paradox (Score:2, Interesting)
First of all I assume by "someone in the future" you mean a human on earth. In this case, one of the simplest ways to avoid the future time travelers paradox is to posit that a backwards time travel of N years must physically be accompanied by a spatial displacement of more than N light years. That way, nobody who travels back in time can interact with anything affecting their own past, since they can't interact outside of their light cone.
Another way out of the time travel paradox is to adopt the "parallel universes" viewpoint put forth in the article, and provide some mechanism for explaining why we always stay in the one universe out of these that has not seen time travelers.
Finally, if by someone in the future you mean aliens from somewhere other than earth, then this problem is also easy to resolve: since we have not seen any aliens at all (roswell notwithstanding), it's unreasonable to expect to find alien time travelers.
Food for thought (Score:3, Interesting)
If Professor A creates a time machine, and uses it to travel back to the past to alter a certain event, say preventing JFK from getting shot. He may effect the timeline, but he will create a branch at the same time. He will continue along that branch and reality forever.
The rest of us on the main trunk will never see that effect that professor A had on the past, since history has already been written for us. Professor A has been lost forever since he will be living in the history he has created.
You could go back in time, but you will never be able to return to THIS reality. That would be the paradox.
He really isn't a nut (Score:5, Interesting)
Re:Why there will never be a time machine (Score:2, Interesting)
In fact thinking about it if this view of time travel is true and workable it would almost seem like a wacked out cult. A person appears and claims to be from the future. They either have schematics for a time machine or they inspire development of one. (We'll ignore they likely outcome that any visitor from the future is locked up with all the Thorazine they'll ever want for the purpose of this discussion). When the machine is built it can't be proven to work. The best evidence any timeline will ever have is one visitor. Would you trust the word of a possible nut ball and step into something that makes matter disappear? I think only borderline psychotics would be nervy enough to do so. Which suggests that the time traveller would be kind of kooky to begin with.
yes and no (Score:2, Interesting)
Re:hey... (Score:5, Interesting)
Re:He really isn't a nut (Score:5, Interesting)
However travelling into the past _is_ a big deal, as it questions a lot of physical fundamentals. What about energy conservation? Would the energy of the matter vanish out of the present? Would it pop out in the past. The particle of course already existed in the past, will exist then twice there? As I've now in the past two times the enery of the particle, have I created new energy?
Simply take a machine that transports a neuron back a second in time, 2 Neurons will exist then in a second before, put the time machine will still run there "a second time", so 3 Neuron will exist a second before, a second later the time machine will again send a neuron back a secnd. 4 Neurons will exist, so on and so on.
Is the ener
Re:hey... (Score:5, Interesting)
Or what have you. Kind of a Sliders type of universe setup.
Kintanon
Umm particles from the future? (Score:5, Interesting)
I see two problems with this:
1.) What would keep the particle appearing in the future from appearing in the same spot? Seems like they'd try to occupy the same space..
2.) how will they know it's the same particle? Guage it's spin maybe?
Im concerned that the experiment could produce positive results, but not positively. Kind of like that fusion bubbles thing not too long ago.
Here's a question though: Is it possible this could be a new way to harness energy? Imagine reclaiming energy from the past...
Re:I don't see how slowing down light helps. (Score:1, Interesting)
On a slightly different note, the speed of information can be faster than light, such as when transmitting a signal over a conducting wire. The electrons themselves move on the order of 1 m/s, but they push all the others in front of them along. Imagine a frictionless tube of sand a billion miles long. Push the sand on one end in with a plunger, and as soon as you do, sand falls out the other regardless of the length of the tube. Imagine just using a really long stick. Weird, huh?
Re:Poignant. (Score:2, Interesting)
He died at the age of 33!! I've never heard of smoking killing someone at such an age. As a 23 yr old smoker myself, that scares the shit out of me. I could be half way dead already.
I'm getting good at quitting though - done it 20 times already today!
Ill explain (Score:5, Interesting)
Time travel is something our minds do on a daily basis, you can imagine future events, sometimes you are right and sometimes you are wrong, traveling into the future allows you to travel into a POSSIBLE future, but no future is THE absolute future,
Time is not mapped, its dynamic, it works like this, everything that can happening, is happening if not in this reality in another.
Its more like sliders than likee the time machine movie, you travel through realities, or mirror universes, according to current theory, its believed theres infinite mirror worlds
A time machine actually isnt a time machine in that sense, its a machine which allows you to go into any reality you want, or create your own reality by modifying the past.
We all create our own reality anyway, the diffrence is with a time machine, YOU have an advantage, you can not only imagine a new reality but literally control the future by modifying the past.
Its like gambling but cheating.
A time machine allows you to essentially cheat.
The reason we dont see anyone coming from the future is, when you travel to the future, the past changes, you can never go back to the original past, if you do go back to the past its a new past thats a mirror of the original one.
I'm convinced anyone who will time travel into the future will never return, basically they'll vanish forever and all will vanish with them
Anyone who travels to the past will vanish forever from our reality
basically time travel is a one way trip.
Re:From the article... (Score:4, Interesting)
What would probably happen is:
Re:The best he can build is a disintegration chamb (Score:2, Interesting)
The real kicker is about how when the dimension travellers get home. When they leave, a little point is set on their display as to which universe to return to. As time passes, the universes multiply, and that single point becomes a band of points--because their universe has already been going on without them. The "widening of the bands" apparently causes these guys to get depressed and off themselves.
This begs the question (with regards to those timelines appearing out of nowhere) about whether a time traveller will be able to direct which universe they could head towards. There was another book, Novelty (can't seem to find the author), that had an idea that you couldn't travel contrafactually (so universes containing many time travellers just got wierder and wierder), so it was possible for a set of parallel universes to exist where people, were their own grandfather, but not a universe where someone killed their grandfather (or if they did, they got kinda stuck in that universe because they couldn't go back, or something like that). Although, the book didn't explore the idea too thoroughly.
Anyways, seeing how nature would sort out this kind of hubris would be damn interesting.
Re:Completely Explainable... (Score:4, Interesting)
Re:Poignant. (Score:2, Interesting)
I have no idea how physicists approach the question of the creation of a contrafactual timeline which removes its own motive for existing
That's an easy one to answer. There is no such thing as Time.
Time is just a concept that's useful to us.
It's easy to check this for yourself. Have you noticed that whatever time it is, it's always the present?
The present moment is all that there is. Eternity is the timeless now.
Even memories are experienced in the present. We're living an ever changing present moment.
Oh, and there's no Space either.
"Not Possible," says Local Slashdot Reader (Score:4, Interesting)
I believe that, in this case, "absence of evidence is evidence of absence". In other words, the fact that we don't already know about time travel is evidence that time travel will never be possible. This gets confusing quickly, but if time travel ever becomes possible, somebody will surely travel to what is our past. While early attempts might be "covert" (a la "Back to the Future") to prevent altering the future, this could only be successful for so long. Even if attempts continued to be made to keep it a secret, somebody at some point would have either told somebody that they met in the past or there would have been rumors or something.
But all references that we hear to the possibility of time travel are based in the future, such as this story about a guy who's "going to do it". Of course, we all know he will fail, because otherwise, we would have already known of his success. At the very least, if he was to ever be successful, we would not be living in a world where he was trying to travel in time to save his dad from cigarettes, but rather in a world where his dad had been saved from cigarettes by his son.
In fact, if time travel were to ever be successful, we would have always known about it, and the quest for time travel would not exist.
It gets more interesting and more confusing as you think about it...
RP
Re:More information (Score:2, Interesting)
Um, no (Score:1, Interesting)
Maybe time travel does/will work for this guy, but he either decides not to change his past for moral/ethical/headache reasons, or doesn't get a chance to do so within his lifetime.
I don't believe that just because we don't see evidence of something that that is in fact evidence that that something doesn't exist. If you're looking for a certain kind of evidence, and that's the wrong kind of evidence, you're not gonna have much luck. Likewise if you don't know that a particular occurance is definate evidence of that thing.
Some said that if this contraption works, all will succeed in doing is whirling objects back or forward in time, out into the middle of space where the Earth once was, or will be. I say: "Hey! that's not a bad thing! It's the new travel craze! Just pop in the time machine, and zip around to the other side of the world hours before you left! Just remember to pack a parachute, eh?
Time travel is ABSOLUTELY impossible. (Score:2, Interesting)
It is absolutely impossible.
The reason I say this so strongly is that I know that it's so. Think about this for a moment. Time is a concept. One cannot travel through a concept.
Time is what people use to the explain the phenomenon of rearrangement of matter. Things are in a different configuration so it is a different 'time'. The only difference from one 'time' to another is the position of all of the matter and energy in the entire universe. To revisit another 'time' would be to observe the precise configuration of all matter in a previous state. Now check you thermodynamics pocket guide, and the relativity manuals you were issued and immagine the energy required to restore every particle and quark to a previous state simultaneously without using any energy from the universe; you can't siphon your own gas tank! And this is further complicated by the theoretical presense of the observer in the data set. Adding 165lbs of matter to the total massof the universe may not be a good thing.
Now recreating the position and vectors for all matter and energy is one problem, but the database to store the coordinate and vector data for all those objects for an infinitely resolved universe is going to HAVE to be quick!
Simply stated. time does not exist. There is only one instance of existance and it's now.
Future travel is simpler (Score:2, Interesting)
Re:Respected? (Score:2, Interesting)
The time machine variations I have seen (ie. massive rotating cylinder, toroid black hole and a few more) only allow you to travel back in time to the moment the machine was set up - and only forward until the time it is dismantled.
It all has to do with creating closed time-like loops, loosely a path through space that allows you to return to the same position at an earlier time. Want to go back further, go around another time. Want to go forward, loop in the other direction. In other words, the 'machine' itself does not move through time. Only you do, by following specific paths around it.
Most time machine conecpts involves extremely dense objects (think neutron star matter or singularities) moving at sizeable fractions of the speed of light. I wonder exactly how much power those lasers of his generate?!
On the subject of forking universes, paradoxes etc., my understanding (IANAP, IAAP-groupie) is that there can be only one time line, which must be consistent. When you apply quantum mechanics to a system with closed time-like loops, the probability wave functions sum to zero for any events which would be paradoxical. So, you can't kill gramps. Think 12 Monkeys.
Oh, and some believe (about 50/50 among those I have spoken to) that the probability waves will sum to infinity for all non-paradoxical events, creating infinite energy densities and blowing up any time machine even as it forms. Hopefully not taking the city/planet/universe with it.
An explanation of why this man is a crank. (Score:2, Interesting)
http://home1.gte.net/res02khr/crackpots/notorious
Professor Mallett's homepage (Score:1, Interesting)
Where in *space* might we go? (Score:1, Interesting)
Perhaps, as someone mentioned before, the travel destination would always be the current location of the machine and one would be limited to times when the machine was functioning.
What about the earth? (Score:3, Interesting)
Malletts explains the limits of time travel (Score:2, Interesting)
I have spoken with Dr. Mallett a few times and trade emails with him. I'm writing a science fiction story based on his ideas, and including him a straight journalism article.
Some comments and jokes about time paradoxes were raised in postings, so I'll hit a few points. Mallet believes that time portals work only from the time they are first opened. If you open a portal this Wednesday, you can receive a visitor from Thursday, but that person can't rush back to Tuesday or Monday.
The only "out" is that perhaps a person could go to a parallel past if there are myraid universes in a multiverse. Then you might get a visitor from Thursday to start your week Monday morning, but because you have no influence on that timeline, I wouldn't bank on it. Then there are issues of conservation of matter and energy to consider, right down to photons even if a person never passes through the portal.
Anyway, Mallett's not a nut. He's a theoretical physicist. Hard to tell them apart, of course, but I'm grateful when new ideas pop up from either.
Erik